Seventy-two hours of continuous polygraphic recording of the EEG, EOG, and EMG of patients hospitalized with neurologic dysfunction (coma) will be made. An individually planned series of meaningful stimuli will be presented to ten comatose patients at periods when the EEG arousal can be expected to be highest, e.g., after neurologic nursing assessments and nursing interventions. The data obtained from these ten patients will be compared to similar data from ten patients in a comparison group, matched for sex, age (within 5 years), depth of coma, and similarity of sleep patterns. The major objectives of the study will be to determine if a planned series of meaningful stimuli presented at periods of greatest EEG arousal will result in more normal sleep cycling and more rapid recovery of alertness compared to the comparison group. The data will also be analyzed to determine if REM sleep is absent from the 24-hour polygraphic patterns of the comatose patients and to determine the feasibility of using the transportable polygraphic recorder in clinical studiesof cycles which may exist in comatose patients (hospitalized in an acute care facility). Clinical and behavioral correlates of the EEG state of arousal will also be determined by clinical observation. The research design will be quasi-experimental; some extraneous variables will remain uncontrolled in the proposed clinical setting.